Well-casing perforator.



C. P. SKINNER. WELL CASING PBRFORATOR. APPLIOATION FILED JUNE 7, 1913.

1, 1 1 2,57U. Patented Oct. 6, 1914 2 SHEETSSHEET 1 2,, 9 gym I be perforated at various at its upper end,

CHARLES E. SKINNER, OF ORCU'TT, CALIFORNIA.

WELL-CASING EERFOBATOB.

Application filed. June 7, 1913. Serial No. 772,346.

To all whom it may concern Be it known that 1, CHARLES P. SKINNER, citizen of the United States, residing at Orcutt, in the county of Santa Barbara and State of California, have invented cer tain new and useful Improvements in Well- Casing Perforators, of which the following is a specification.

My invention relates to a new and improved form of perforator for perforating or punching holes in the casings of oil wells and the object of my invention is to provide a tool which may be lowered into the casing and which, when positioned, will be p self-supporting during the perforating operation.

A further object of my invention is to provide a tool of the above described character by means of which the casing may levels without the necessity of removing the tool from the casing.

With these and other objects in view, my invention will be more fully described, illustrated in the accompanying drawings, and then specifically pointed out in the claims which are attached to and form a part of this application.

In the drawings: Figure 1 is a sectional view of a portion of a well casing, showing the tool in place, the tool being shown partially in section and in the position in which it is placed when being lowered into the casing; Fig. 2 is a side elevation, partially in section, of the tool showing the position of the parts when the tool has been locked against farther downward casing; Fig. 3 is a side elevation, partially in section, of the tool showing the manner in which the punches, by which the casing is perforated, are extended; Fig. 4: is a transverse sectional view on the line 44 of Fig. 3,1ooking upwardly.

Corresponding and like parts are referred description and indicated in all the views of the drawings by the same reference characters.

My improved perforator for well casings consists primarily of two parts, a perforator proper and a perforator support 11. The perforator proper includes a hollow cylindrical body forming abowl or cage 12 in which is mounted the punch carrying mandrel 13. This bowl or cage is closed save for an opening through which the shank 1a of the mandrel Specification of Letters Patent.

movement in the- Patented @ct. 56 1914.

extends and is closed at its lower end by a removable cap block which, when the tool is assembled, is secured in place by a plurality of cap screwslfi.

The bore .of the cage is slightly greater in diameter than the diameter of thebody portion of the mandrel 13 and the cage exclusive of the cap block is considerably longer than the body portion of the mandrel. The cap block corresponds in shape to the shape of the cage and the cage and block are proportioned to pass freely within the well casing as shown in Fig. 1 in which a well casing is conventionally shown at 17. The peripheral faces and cap block are provided with a plurality of spaced apart, longitudinally extending leakage grooves 18 for the passage of oil or water, thereby permitting the tool to be lowered into a casing below the liquid level therein.

The shank 14C of the punch carrying mandrel 13 has its free end threaded as at 18' for threaded attachment with a tool pin 19 of any preferred type. The lower end of the body portion proper of the mandrel 13 is provided at its peripheral edge with a plurality of equally spaced apart recesses 20 and pivoted upon pins 21 extending across these recesses are punches 22 which are substantiallv rectangular in shape and which are narrowed at their lower ends by rounding off their inner faces as shown at 23. The cage 12 is provided at its lower end with a plurality of slots 24 through which the punches may be extended and the upper face of the cap block 15 is cutaway in alinement with these punches to provide inclined faces 25 against which the rounded faces 23 of the punches engage when the mandrel 13 is lowered in the cage and which therefore cause the outward movement of the punches through the slots 2% of the cage.

The cap block 15 is provided centrally with a bore 26 to slidably receive one end of a second mandrel or shaft 27 which forms the body portion of the 'tool support. The upper face of the cap block 15 is counterbored as at 28 to seat the enlarged conical head 29 of this second mandrel when the cage and cap block are raised with respect thereto by the upward raising of the first mandrel or punch carrying mandrel. The free end of the supporting mandrel 27 extends a considerable distance below the cap of both the cage block and is provided with a pair of spaced collars 30 and 31 which are secured against movement upon the mandrel by set screws 32. A plurality of bowed springs 33 are secured by their ends to these collars and are so proportioned as to frictionally engage against the inner face of the well casing as clearly shown in Fig. 1 of the drawings. The upper portion of the mandrel 27 is provided with a longitudinally extending channcl or recess 34 and a trigger 35 is pivotally mounted by its lower end in the lower end of this recess. The upper end of the mandrel is further recessed to provide a socket 36 coinnnuiicating with the upper end of the recess 34: and forming a seat for a helical spring 37 which bears against the free end of the trigger 35 and tends to normally maintain the same in extended position, as shown in Fig. 2. The free end of the trigger 35 is cut-away to form an angular seat 38 which engages beneath the cap block 15 when the head 29 of the supporting mandrel is seated in the socket 28 thereof. The strength of the springs 33 is such that their engagement against the inner face of the well casing is sufiicient to just support the weight of the cage 12 and cap block 15 but not to support the weight of the punches and punch carrying mandrel in addition.

In operation, the su porting mandrel is moved upwardly, the trigger 35 having been depressed within its seat until the head 29 of the mandrel engages against the lower end of the body portion of the punch carrying mandrel 13. The tool is then lowered into the well casing, the weight of the entire tool being suiiicient to overcome the action of the springs 33. When the tool has been lowered to the desired level within the well, the punch carrying mandrel 13 is raised carrying with it the cage 12 and cap block 15 until the head 29 of the supporting mandrel is seated in the socket 28. The trigger 35 then springs outwardly into engagement with the cap block as shown in Figs. 2 and 3 of the drawings. When so disposed, the supporting mandrel and springs will support the weight of the cage and cap block and any downward movement of the punch carr ing mandrel, before it engages the cap bloc r, will, of course, have no tendency to move either the cage or cap block and the supporting mandrel and springs will therefore support the tool in adjusted position. When so positioned force is exerted upon the tool pin to drive the punch carrying inandrel 13 downwardly and upon its downward movement the curved faces of the free ends of the punches engage the inclined faces 25 of the cap block recesses to deflect the punches outwardly radially and into active engagement against the inner face of the well casing from which time the punches also assist in holding the tool in position.

By applying suflicient force to the tool pin the punches may be driven completely through the casing, perforating the same. After the casing has been perforated the toolmay be raised from the casing merely by lifting up on the tool pin as the raising of the punch carryin mandrel will act to simultaneously wit draw and raise the punches which is carries. It will of course be apparent that the casing may be perforated at a number of dilferent levels if desired without necessitatin the removal of the tool from the well during the entire 0 eration, providing the tool is lowered to t is lowest level desired before the cage is raised to lock the supporting mandrel in active position and the casing therefore perforated first at the lowest polnt desired and then at successively higher levels.

I do not wish in any way to limit myself to the specific details of construction illustrated in the drawings or described in the foregoing specification, as various minor changes, within the scope of the appended claims, may be made at any time without in the slightest degree departing from the spirit of my invention.

Having thus described the invention, what is claimed as new is:

1. A perforator for well casings including a cage closed at its ends, a punch carrying mandrel reciprocally mounted in the cage with a reduced extension projecting through the top thereof, punches carried by the mandrel and movable radially through openings formed in the cage wall upon downward movement of the mandrel in the cage, and means carried by the cage for supporting the same when lowered in position in the casin 2. perforatorfor well casings including a cage closed at its ends, a punch carrying mandrel reciprocally mounted in the cage, punches carried by the mandrel, means for reciprocating the mandrel in the cage, a mandrel shaft movable through the bottom of the cage and provided at its upper end with, a head adapted to seat in a socket in the bottom of the cage and adjacent to the head with a catch adapted toengage beneath the cage to lock the shaft against movement independent of the cage, and casing-engaging elements carried by the shaft.

3. A perforator for well casings including a cage closed at its ends, a punch carrying mandrel reciprocally mounted in the cage, punches carried by the mandrel, means for reciprocating the mandrel in the cage, 9. mandrel shaft movable through the bottom of the cage and provided at its upper end with a head adapted to seat in a sec at in the bottom of the cage and adjacent to the head with a catch ada ted to engage beneath the cage to lock the s aft against movement independent of the cage, and casing-engaging iso elements carried by the shaft; said elements being adapted to engage the casing sufliciently to support the cage but not sufiicientl to support the cage and its mandrel.

4. X perforator for well casings including a cage provided in its outer face with longitudinally extending leakage grooves, said cage being closed at its upper end, a mandrel mounted in the cage for reciprocatory movement therein and having a reduced extension projecting from an opening in the closed upper end of the cage, a cap block secured to and closing the lower end of the cage and provided centrally with a socket and with a bore forming a reduced continuation of the socket, the wall of said cage being provided with slots and the upper face of the block with channels registering with the slots, punches carried by the mandrel and adapted upon downward movement of the mandrel with respect to the cage to engage the cap block and be forced radially through the slits in the cage to perforate a casing, a mandrel shaft movable through the bore of the cap block and provided with a head adapted in one position to engage against the lower face of the first mandrel and in another position to seat in the socket of the cap block, a spring-pressed trigger carried by the shaft and adapted to automatically engage beneath the cap block when the head of the shaft is' seated in the socket thereof, collars carried by the free end of the mandrel shaft, and bowed springs connecting the collars and adapted for frictional engagement with a casing to support the mandrel shaft and cage.

In testimony whereof I aflix my signature in presence of two witnesses.

CHARLES r. SKINNER. [L 8.]

Witnesses:

CHAs. SHAW, J. F. HARTY. 

